Flow Field Analysis of a Detailed Road Vehicle Model Based on Numerical Data

Abstract

The three-dimensional flow field of a detailed road vehicle model with focus on the importance of engine and underbody representation is studied. Further, issues of vortical flows are explored. Especially the presence of wheels and a detailed underbody has a major impact on the developing flow field. The numerical data provides the necessary insight into the main flow features such as the dominant wake structure typical for a bluff body. URANS simulations accounting for the inherent unsteadiness of the flow were performed in OpenFOAM$^{{\textregistered }}$ and were validated with experimental force and velocity field measurements using particle image velocimetry at a corresponding Reynolds number of 3 million. The results for the flow field showing a number of secondary effects interacting with the large areas of separated flow along and downstream of the model are discussed in detail. Another emphasis of the analysis is placed on the dependence of the wake structure on the characteristics of the underbody flow and the accuracy of the integral drag and lift coefficients. The study shows the particular importance of considering the impact of model simplifications on the global flow field of a road vehicle model.